diff --git a/pipeline/journey_times/__main__.py b/pipeline/journey_times/__main__.py
index cde9480..6297f09 100644
--- a/pipeline/journey_times/__main__.py
+++ b/pipeline/journey_times/__main__.py
@@ -71,9 +71,12 @@ def main():
     prior_results: list[JourneyResult] = []
     if checkpoint_path.exists():
         checkpoint_df = pl.read_parquet(checkpoint_path)
-        completed_postcodes = set(
-            checkpoint_df.filter(pl.col("public_transport_easy_minutes").is_not_null())["postcode"].to_list()
+        # Deduplicate checkpoint rows per postcode, preferring rows with data
+        checkpoint_df = (
+            checkpoint_df.sort("public_transport_quick_minutes", nulls_last=True)
+            .unique(subset=["postcode"], keep="first")
         )
+        completed_postcodes = set(checkpoint_df["postcode"].to_list())
         prior_results = [
             JourneyResult(
                 postcode=row["postcode"],